Apparatus and Methods for Anastomosis

ABSTRACT

Apparatus and methods for performing an anastomosis. More particularly, the apparatus may be used to perform a single or multiple anastomosis with the ability of maintaining fluid flow (e.g., blood) through the anastomosis vessel according to one aspect of the invention.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application hereby claims priority to copending provisionalapplication No. 60/127,862, which was filed on Apr. 5, 1999, and whichis hereby incorporated herein, by reference thereto, in its entirety.

FIELD OF THE INVENTION

The present invention relates to apparatus and methods for performing ananastomosis. The apparatus may be used to perform a single or multipleanastomosis with the ability of maintaining fluid flow (e.g., blood)through the anastomosis vessel.

BACKGROUND OF THE INVENTION

The occlusion of the arteries can lead to insufficient blood flowresulting in discomfort and risks of angina and ischemia. Significantblockage of blood flow in the coronary artery can result in damage tothe myocardial tissue or death of the patient. In most cases, occlusionof the artery results from progressive long term deposits of plaquealong the artery wall. While such deposits may be concentrated andocclude the artery at a particular site, the deposits are most certainlypresent throughout the arteries and the vascular system.

Coronary artery bypass graft (CABG) surgery is a surgical procedureperformed in severe cases of coronary blockages. CABG procedures involveanastomosing an artery to a vascular graft which restores the flow ofblood by establishing another pathway around the occluded vasculature.One problem encountered in the procedure is the need of performing theprocedure while simultaneously maintaining sufficient function of thepatient's circulatory system.

A CABG procedure may involve arresting the heart so that blood flow isdiverted from the vessel to be anastomosed. The patient's bloodcirculation is maintained by a cardiopulmonary bypass (CPB). This bypassis accomplished by diverting the blood flow at selected arteriallocations. The blood is diverted to the bypass system for release ofcarbon dioxide and subsequent oxygenation. Then, the blood is returnedto the patient via a pump. Examples of these procedures are found inU.S. Pat. No. 5,799,661 to Boyd et al. which discloses a device andmethod for performing CABG surgery for multi-vessel coronary arterydisease through port-access or closed-chest thorascopic methods; andU.S. Pat. No. 5,452,733 to Sterman et al. which discusses performinggrafts with an efficacy equal to or greater than conventional opensurgical bypass techniques.

Another CABG procedure involves operating on a beating heart andeliminates the need for a CPB. However, the procedure still requiresdiverting blood flow for a proximal anastomosis, such as one whichattaches graft material (e.g., a graft vessel) to the ascending aorta.

First, the blood flow may be diverted by aortic clamping. Among thedrawbacks associated with aortic clamping are an increased chance oftrauma to the arteries caused by ligatures at the clamped site and thepossible dislodging of plaque within the clamped vessel wall. Asmentioned above, the arterial bypass may be required due to the depositsof plaque which have occluded the vessel. However, the plaque istypically present throughout the artery and is not limited to theoccluded location. Clamping the artery creates a risk of plaque beingreleased into the blood stream. This release of plaque has the potentialof causing a stroke, occlusion of a smaller peripheral vessel, or othervascular trauma. In a beating heart procedure, full clamping (i.e.,cross clamping) of the aorta for graft attachment at the proximalanastomosis is not feasible. Therefore a side biting clamp is used toclamp off only a portion of the cross-section of the aorta, where theproximal anastomosis is performed. This type of clamping procedure posesthe same risks described above with regard to cross clamping, e.g., therisk of release of plaque and resultant cause of a stroke, occlusion ofa smaller peripheral vessel, or other vascular trauma.

Second, the blood flow may be diverted by the use of a balloon catheterwithin the aorta, such as described in U.S. Pat. No. 5,868,702, forexample. Drawbacks of using a balloon catheter in creating a seal todivert blood flow include the possibility of disturbing plaque depositsand creating particles in the blood stream, the chance that the ballooncatheter may move within the aorta disrupting the seal and resulting inblood loss, and trauma to aortic tissue caused by the pressure needed tocreate the seal.

PCT Patent WO 98/52475 to Nobles et al. attempts to address problemsassociated with diverting the blood flow. Nobles et al. provides amethod and device for creating an area of hemostasis within a bloodvessel without interrupting the flow of blood through the vessel whicheliminates the need to clamp the vessel. However, the Nobles et al.device requires the withdrawal of the hemostasis device prior toobtaining a tight seal between the graft and vessel. Therefore, sincethe area of hemostasis is lost upon the retrieval of the hemostasisdevice, the artery is open and blood is lost until the sutures aretightened.

Yet another problem related to CABG procedure lies in the procedure ofsuturing the vessels to create a tight seal. To ensure the integrity andpatency of the anastomosis, the graft and vessel to be joined must beprecisely aligned with respect to each other. If one of the tissues isaffixed too close to its edge, the suture can tear through the tissueand impair both the tissue and the anastomosis. Another problem is that,even after proper alignment of the tissue, it is difficult and timeconsuming to pass the needle through the tissues, form the knot with thesuture material, and ensure that the suture material does not becomeentangled. These difficulties are exacerbated by the small size of theartery and graft. Another factor contributing to the difficulty of theCABG procedure is the limited time available to complete the procedure.The surgeon must complete the graft in as little time possible due tothe absence of blood flowing through the artery. If blood flow is notpromptly restored, sometimes in as little as 30 minutes, the tissues theartery supplies may experience significant damage or necrosis. Asmentioned above, surgeons are under pressure to reduce the cross-clamptime, yet, an incomplete suture may result in a leak in the tissueapproximation between the vessel and graft. Moreover, the tissueapproximation must be smooth and open. Hence, the suture cannot behastily performed.

Additionally, the difficulty of suturing a graft to an artery usingminimally invasive surgical techniques, where the surgeon uses ports toaccess the internal organs to perform the procedure, has effectivelyprevented the safe use of complicated suturing technology incardiovascular surgical procedures. Accordingly, many procedures areperformed invasively and require a stemotomy, an opening of the sternum.As a result, the recovery times for patients is significantly increased.U.S. Pat. No. 5,868,763 to Spence et al. attempts to circumvent thesuturing process by attaching the vessels to a cuff device. Spence etal. utilizes a passageway for continued blood flow so there is noclamping of the artery.

Houser et al., in U.S. Pat. No. 5,989,276, discloses various devices andtechniques for performing bypass, one of which includes a device whichcan be intralumenally originated. Various other clamping arrangementsare provided for securing a graft to a vessel without the use of suturesor other fasteners.

All of the problems discussed above are multiplied in those cases wherea multiple anastomosis is required. In those cases where multiple bypassprocedures are performed, the patient will naturally be subject toincreased risks as multiple grafts must be sutured to perform thebypass.

There remains a need for improved anastomosis systems.

SUMMARY OF THE INVENTION

The present invention involves apparatus and methods for connectingtissue. This invention may, for example, be used to secure one vessel toanother, such as in a vascular anastomosis while maintaining blood flowwithin the vessel.

According to one aspect of the invention, an anastomosis apparatus isprovided comprising a tubular member having an end with an edge adaptedto form an opening in a vessel wall and an anchor member, whichcomprises a flexible shaft and a piercing member, slidably coupled tothe tubular member. Preferably, a generally circular centering disk witha plurality of spikes is also provided to slide down along the flexibleshaft of the anchor member.

During the surgery, a physician pushes the shaft of the anchor member toinsert the piercing member through the vessel wall. The piercing memberis then pulled back against the vessel wall. Once the piercing member isin place against the inner wall of the vessel, the centering disk is putin place and pushed against the outer wall of the vessel, therebyclamping the vessel wall between the centering disk and the piercingmember. The tubular member is then moved over the shaft, centered by thedisk and rotated to cut an opening through the vessel wall. Thereafter,the piercing member is used to coordinate with the centering disk toretain and retrieve the tissue cut by the tubular member. Next, anocclusion member is advanced within the tubular member through theopening in the vessel wall in order to substantially occlude suchopening and form an area of hemostasis. The tubular member can then beretrieved, leaving the occlusion member in place, after which a graft isslid down along the occlusion member shaft for creating an anastomosiswith the vessel.

According to one embodiment, the occlusion member comprises a cannula.According to another embodiment, the occlusion member comprises aradially expandable member, which can be an expandable brush-likemember, an umbrella, a flexible cup or an inflatable balloon.

According to another aspect of the invention a cannula having an endportion adapted to pierce through a vessel is provided. The cannula maybe passed through a vessel wall and a graft secured to the vesseladjacent to the cannula to facilitate an anastomosis without clampingthe vessel, thereby avoiding the risk of dislodgement of plaque from theinner wall of the vessel which is incurred with clamping.

According to another aspect of the invention, a trocar adapted toreceive the cannula and allow it to pivot is provided. The cannula,thus, may be repositioned to pierce the vessel wall at differentlocations and perform multiple anastomoses without relocation of thetrocar in the vessel wall.

According to another aspect of the invention, a surgical fastener orclip cartridge is provided. One or more surgical fasteners may be loadedin the cartridge with ends of each fastener selectively releasable fromthe cartridge to anchor in either the graft or vessel to which the graftis to be attached. According to one cartridge embodiment, first andsecond tubular members are slidably coupled to one another and at leastone surgical fastener placed therein with one end of the fastenerengaging the first tubular member and another end of the fastenerengaging the second tubular member.

According to yet another aspect of the invention, a dual-stage releasefastener is provided which includes a clip movable between an open and aclosed configuration and having a memory biased to the closedconfiguration. A first mechanical restraint is coupled to a firstportion of the clip and is adapted to bias the first portion toward theopen configuration. A second mechanical restraint is coupled to a secondportion of the clip and is adapted to bias the second portion toward theopen configuration.

The first and second mechanical restraints may be independentlymanipulatable to allow independent closure of the first and secondportions of the clip.

According to still another aspect of the invention, an anastomosisapparatus is provided comprising a tubular member having an end with anedge adapted to form an opening in a vessel wall and an anchor member,which comprises a flexible shaft and a piercing member, slidably coupledto the tubular member. Preferably, a generally circular centering diskwith a plurality of spikes is also provided to slide down along theflexible shaft of the anchor member. An adapter is mounted on thetubular member that forms the opening. The adapter includes wells inwhich needles are held in a predetermined orientation adapted forpiercing through the vessel wall from the inside out, upon passing theadapter into the vessel and then pulling it back to perform the piercingaction. Two-stage release fasteners may be used in conjunction with theadapter so as to affix the fasteners to the vessel after piercing itwith the needles and then fixing the fasteners to a graft in a lateroperation.

The above is a brief description of some advantages of the presentinvention and deficiencies in the prior art. Other features, advantages,and embodiments of the invention will be apparent to those skilled inthe art from the following description, accompanying drawings, andclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of heart illustrating an example of ananastomosis and trocar placement site.

FIG. 2 is a sectional view of a cannula constructed according to theprinciples of the present invention and disposed within a trocar havinga configuration according to another aspect of the invention.

FIG. 3 is a partial sectional view of the trocar of FIG. 2.

FIG. 4 is a side view of the trocar positioned on a vessel wall.

FIG. 5 is a sectional view of another cannula of the present inventiondisposed in the trocar of FIGS. 2-4.

FIG. 6A is a partial sectional view of a configuration of a surgicalfastener cartridge according to the present invention.

FIG. 6B is a front view of the cartridge of FIG. 6A.

FIG. 6C is a plan view of one of the surgical fasteners of FIGS. 6A and6B in a released state.

FIGS. 7-11 show a method of preparing an anastomosis in accordance withthe principles of the present invention.

FIG. 7 shows a sectional view of the trocar and cannula of FIG. 2positioned in an artery with the piercing element removed.

FIG. 8 shows a sectional view of the placement of a graft over thecartridge of FIG. 6A.

FIG. 9 shows a sectional view of the partial release of the assembly ofFIG. 8 with one end of the fasteners released and anchored to the graft.

FIG. 10 illustrates the complete removal of the tubular member whichrestrains the released fastener end.

FIG. 11 shows aligning and introducing the cartridge into the cannula.

FIG. 12 shows the cartridge in place in the cannula and the releasedfastener ends engage the vessel.

FIG. 13 shows the release of the locking member for the other ends ofthe fasteners.

FIG. 14 shows withdrawing the cannula and second tubular member torelease the second ends of the fasteners so they may engage the innerwall of the vessel.

FIG. 15A is a sectional view of another proximal anastomosis device witha punch, an anchor member and a centering disk.

FIG. 15B is a sectional view of the device of FIG. 15A after an openingis created in the vessel wall by the punch and the tissue cut is beingretrieved.

FIG. 15C is a sectional view of the device of FIG. 15A with an occlusionmember comprising two coaxial cylinders and a radially expandable memberattached to the distal end of the inner cylinder.

FIG. 15D is a sectional view of the device of FIG. 15A with the punchretrieved and a graft slid over the radially expandable member to beattached to the vessel by a plurality of self-closing fasteners.

FIG. 15E is a perspective view of the device of FIG. 15A with a punch,an anchor member and a centering disk.

FIG. 15F is a perspective view of the device shown in FIG. 15C.

FIG. 16A is a sectional view of another proximal anastomosis device,with a radially expandable member comprising a plurality of bristles.

FIG. 16B is a sectional view of the device of FIG. 16A, with theplurality of bristles radially expanded to occlude the opening in thevessel wall after the outer cylinder is withdrawn.

FIG. 16C is an end view of the device of FIG. 16A with a retaining ringattached to the inner cylinder to bind a bundle of bristles.

FIG. 16D is an end view of the device of FIG. 16A with the bristlesattached to the inner wall of the hollow inner cylinder.

FIG. 16E is a partial sectional view of the device of FIG. 16A with thepunch withdrawn, the occlusion device in place with the bristlesexpanded or deployed, and a plurality of fasteners inserted to attach agraft to the vessel wall.

FIG. 16F is a sectional view of the device of FIG. 16A with the outercylinder slid down over the bristles after an anastomosis has beenformed.

FIG. 16G is a sectional view of the device of FIG. 16A with theocclusion device being withdrawn.

FIG. 17A is a sectional view of another proximal anastomosis device,with a radially expandable member comprising an inflatable membrane anda plurality of fasteners attached to the membrane.

FIG. 17B is a sectional view of the device of FIG. 17A with the membraneinflated to occlude the opening in the vessel wall.

FIG. 17C is a sectional view of the device of FIG. 17A with thefasteners piercing through a graft to attach the graft to the vessel.

FIG. 17D is a sectional view of the device of FIG. 17A with the membranedeflated after the anastomosis is formed.

FIGS. 17E-17K are detailed drawings of a fastener and portions thereof,which may be used in connecting grafts to vessels, according to thepresent invention.

FIG. 18A is a sectional view of another proximal anastomosis device,with a flexible sheath capable of expanding with the membrane.

FIG. 18B is a sectional view of the device of FIG. 18A with sheathexpanded with the inflated membrane.

FIG. 18C is a view of a roll-up sheath with an expandable membranetherein.

FIG. 18D is a sectional view of the device of FIG. 18A, with a graftbeing slid down for anastomosis.

FIG. 18E is a sectional view of the device of FIG. 18A with the graftattached to the vessel by a plurality of fasteners.

FIG. 19A is a perspective view of another proximal anastomosis devicecomprising a skeleton which supports an umbrella-like occlusion member.

FIG. 19B is a sectional view of the device of FIG. 19A with theumbrella-like occlusion member in a folded state within the outercylinder.

FIG. 20A is a sectional view of another example of a proximalanastomosis device with a punch, an anchor member and a centering disk.

FIG. 20B is a sectional view of the device of FIG. 20A after the tissuecut has been retrieved and the punch or cutting member has been furtherinserted within the vessel.

FIG. 20C is a sectional view of the device of FIG. 20A with an occlusionmember inserted into the vessel and the cutting member having beenpulled back to push the protruding needles through the vessel wall.

FIG. 20D is a sectional view of the device of FIG. 20A with the punch orcutting member retrieved and the occluding member in place, inpreparation for placement of a graft. 2

FIG. 20E is a sectional view of the device of FIG. 20A with the punch orcutting member retrieved and a graft in place and partially anastomosedto the vessel.

FIG. 20F is a sectional view of the device of FIG. 20A with the grafthaving been anastomosed to the vessel and with the occluding devicebeing withdrawn.

FIG. 21A is a partial schematic drawing of a two-stage release fastenerfor use with the proximal anastomosis device of FIGS. 20A-20F, forexample.

FIG. 21B is a partial schematic view of the fastener of FIG. 21A afterone end of the fastener has been released.

FIG. 21C is a partial schematic view of the fastener of FIG. 21A afterboth ends of the fastener have been released.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally involves methods and apparatus forperforming an anastomosis and may be used, for example, in bypassprocedures. As used herein, the term graft includes any of thefollowing: hemografts, autologous grafts, xenografts, allografts,alloplastic materials, and combinations of the foregoing.

Referring to FIG. 1, a heart (100) is shown in section with the aortadesignated with reference numeral (102). One possible anastomosis siteis on aorta (102). Two openings, generally designated with referencenumeral (104), indicate where a cannula (described below) may bepositioned to facilitate the anastomosis. It should be understood,however, that although an aortic anastomosis site is shown, theinvention can be used in other areas of the human anatomy where onedesires to connect a graft to tissue, or tubular structure.

According to one aspect of the invention, a cannula having a distalportion adapted to pierce at least one wall portion of a vessel and aproximal portion is provided. The cannula may be used, for example, tocreate an area of hemostasis within the vessel and facilitate ananastomosis while allowing blood to flow through the vessel. In apreferred method, the cannula is passed through a vessel wall from theinterior to the exterior of the vessel to create a hemostasis areawithin the cannula and within the vessel hole created thereby, as willbe described in more detail below.

Referring to FIG. 2, a cannula constructed according to the principlesof the present invention is shown and generally designated withreference numeral (200). Cannula (200) generally includes a distalportion (202) adapted to pierce tissue and a proximal portion (204).Cannula (200) includes lumen (206) which extends the entire length ofproximal portion (204). Lumen (206) allows access inside or through avessel, while cannula (200) forms an area of hemostasis upon insertionof cannula (200) through a portion of a vessel wall. The distal portionof the cannula is configured to pierce tissue, and may comprise a memberhaving a generally cylindrical outer surface and a tapered inner surfacewhich forms a generally frustoconically shaped cavity (208). The distalend (210) of distal portion (202) tapers to an annular point. A proximalend (204) of the cannula is shown to have an expanded diameter. Thelength of the cannula (200) may vary depending on, for example, the sizeof the anastomosed vessels. It is further noted that although the distaland proximal portions (202, 204) are shown as separate elements, theymay be integrally formed as a single unit to form the cannula (200). Theproximal and distal portions may be constructed from a variety ofmaterials. For example, the proximal portion may be plastic. It also maybe constructed to be flexible so that it may be deliveredendovascularly. In addition, the distal portion may be metal such asstainless steel.

The cannula may be introduced endovascularly or passed through a vesselwall to position it within a vessel. In the latter case, a trocar may beused. According to another aspect of the invention, a trocar having avarying diameter lumen may be used to allow the angular position of thecannula to be changed. Referring to FIG. 3 a trocar (300), which mayfacilitate such movement is shown. Trocar (300) generally includes anannular member (302) which forms an annular passageway or lumen (304)which is shown with a varying diameter along a longitudinal direction ofthe trocar (300). The diameter of the lumen of the embodiment shownincreases in both directions away from the central portion (306) ofmember (302). A portion of the increasing diameter of the lumen is shownin FIG. 4. The size of the lumen depends on the diameter of the cannulato be used therewith. A flange (308) may be provided with the trocar(300) to enhance the securement to the vessel as is conventional to theart. A seal (310) is located within the passageway (304).

FIG. 4 illustrates a front view of the trocar (300). Flange (308) may beattached to the vessel wall (312) with sutures (314) with the seal (310)positioned outside the vessel.

Referring to FIG. 5, another cannula generally designated with referencenumeral (500) is shown positioned within trocar (300) according toanother embodiment of the present invention. It should be understood,however, that cannulas (200, 500) can be used alone or with othertrocars. Cannula (500) is the same as cannula (200) with the exceptionthat distal portion (502) varies in construction. Proximal portion (504)is the same as proximal portion (204) and may include enlarged diameterportion (507) to act as a stop and prevent entry of the distal end intothe trocar as in the case of enlarged diameter portion (207). Distalportion (502) includes a cylindrical portion (508) forming a cavity(509) and having an annular edge (510), that may be squared as shown inthe drawing. Adjacent to cylindrical portion (508) is reduced diametercylindrical portion (512) which is adapted to fit in the lumen (506).Cylindrical portion (512) includes a bore (514) for receiving a rod(516) from which pointed member or conical punch (518) and ring holder(520) extend. The portion of head (518) which is adjacent to edge (510)has an outer diameter greater than the inner diameter of the edge, sothat the pierced tissue passes over the head and is pressed against theedge.

According to another aspect of the invention, a surgical fastener orclip cartridge or retainer is provided and may be used with any cannuladescribed above to make an anastomosis. Referring to FIG. 6A, one clipsurgical fastener cartridge (600) is shown in accordance with thepresent invention. Cartridge (600) generally includes a plurality offasteners (603), which may comprise super-elastic or shape memorymaterial, within a first tubular member or sleeve (604) and a secondtubular member or sleeve (602). The tubular members are slidably coupledto one another. One end of the fasteners (603) are biased against thesleeve (602) and the other ends biased against the sleeve (604) byplacement between a rod (610) and annular protrusion (612).

FIG. 6B shows a front view of the cartridge of FIG. 6A. Although thecartridge (600) is shown to have 6 fasteners or clips (603), the numberof fasteners or clips (603) may vary depending on the particularprocedure. FIG. 6A also illustrates rod (610) extending through aproximal end (614) of the cartridge (600). It is also within the scopeof this invention to have rod (610) extending through the opposite endof the cartridge retainer (600).

FIG. 6C illustrates a fastener or clip (603) in accordance with theinvention. In this figure, the clip is illustrated in an unrestrainedshape. The clip (603) is placed in the cartridge (600) and restrained toa second shape as shown in FIG. 6A. One embodiment of a fastener or clipcomprises a deformable wire made from a shape memory alloy. A nickeltitanium (Nitinol) based alloy may be used, for example. The Nitinol mayinclude additional elements which affect the yield strength or thetemperature at which particular pseudoelastic or shape transformationcharacteristics occur. The transformation temperature may be defined asthe temperature at which a shape memory alloy finishes transforming frommartensite to austenite upon heating (i.e. A_(f) temperature). The shapememory alloy preferably exhibits pseudoelastic (e.g., superelastic)behavior when deformed at a temperature slightly above itstransformation temperature. At least a portion of the shape memory alloyis converted from its austenitic phase to its martensitic phase when thewire is in its deformed configuration. As the stress is removed, thematerial undergoes a martensitic to austenitic conversion and springsback to its original undeformed configuration. When the fastener or clipis positioned within the cartridge (600) in its deformed configuration,a stress is present to maintain the fastener or clip tightly against thefirst and second tubular members described above. In order for thepseudoelastic fastener or clip to retain sufficient compression force inits undeformed configuration, the clip should not be stressed past itsyield point in its deformed configuration to allow complete recovery ofthe wire to its undeformed configuration. It is to be understood thatthe fastener or clip may comprise other materials as well.

Referring to FIGS. 7-14 a method of preparing an anastomosis inaccordance with the principles of the present invention will bedescribed. In FIG. 7, a trocar (300) is placed into a wall of a vessel.The piercing cannula (200) is passed through the trocar (300) andadvanced through another wall portion of the vessel. The distal portion(202) may then be removed from the cannula.

Referring to FIGS. 8-10, a tubular graft (G) is slid over first tubularmember (602) of cartridge (600). Tubular member (602) then is withdrawnto remove the bias against one end of the fasteners and allow them topenetrate the graft while moving toward a relaxed state (FIG. 9). Thefirst tubular member (602) may then be completely removed (FIG. 10). Thesecond tubular member (604) and graft are then aligned with cannulaproximal end portion (204) with rod (610), (FIG. 11) and the secondtubular member seated against the cannula proximal portion (292) (FIG.12).

Rod (610), which extends through the cannula proximal portion and outfrom its other end, is pulled to unlock and allow release of other endsof the fasteners (FIG. 13), which are released when cannula proximalportion (204) is withdrawn with second tubular members (604)fractionally fit therein (FIG. 14). Both ends of the clips are thenanchored on the inner and outer walls of the vessel, thereby securingthe graft thereto.

According to another aspect of the invention as shown in FIGS. 15A-15D,a tubular punch or cutting tool (704) having a distal end (705) adaptedto create an opening in a vessel wall (714) is provided. In the exampleshown, distal end (705) includes a knife edge for cutting though thetissue of the vessel wall. Alternatively, other types of cutting edgescould be employed, such as serrated edges, etc, as would be apparent tothose of ordinary skill in the art. An anchor member (728) is slidablylocated within the cutting tool (704). Anchor member (728) has aflexible shaft (707) with a harpoon-like piercing member (708) attachedor integral with a distal end thereof. The piercing member (708) isconfigured to enable relative ease in piercing the vessel wall, while atthe same time making it difficult to pull the piercing member back outof the vessel wall. For example, The “harpoon-like” design may includeone or more barbs (709) extending from or near the distal end of theshaft (707). It is preferable, when piercing the vessel wall with the“harpoon-like” piercing member (708) to rotate the shaft (707) somewhatafter the piercing member (708) has passed through the vessel wall, tomake it more difficult for the barbs (709) to find their way into areturn pathway which would be the same pathway through which theyentered. Alternatively, the piercing member may be configured to beexpandable after it passes through the vessel wall, e.g., the piercingmember may have an “umbrella-like” actuation (not shown), in whichstruts expand so as to form an area much larger than the originaloutside diameter of the piercing member, and approaching an area equalto the area of tissue to be excised. Once opened, the umbrella likemember would then be pulled flush against the inner wall of the vesselin preparation for clamping with a disk (720) (described below).

The shaft (707) may be formed from medically acceptable polymers,stainless steel or Nitinol, for example and is flexible, yet stiffenough to have sufficient column strength to push the piercing memberthrough the vessel wall. For normal CABG surgery, the tubular punch(704) preferably has an inner diameter between about 3.0-6.0 mm and awall thickness between about 0.150-0.200 mm.

Whether barbed, umbrella-like, or some other expanding configuration,the piercing member (708) is tapered, and preferably pointed, in its“pre-entry” configuration, in order to pierce the vessel wall (FIG.15E). The piercing member may be affixed to the flexible shaft (707) byglue or equivalent fixation methods, or can be an integral part of theshaft itself.

Once piercing member (708) has pierced the wall of vessel (714) and theoperator has either rotated the shaft (707) (barbed configuration) orexpanded the piercing member and pulled it back against the inner wallof the vessel (714) (umbrella-like or other expanding configuration), agenerally circular centering disk (720) may be slid down along theflexible shaft (707), as shown in FIG. 15A. The shaft (707) may beprovided with serrations (711) similar to a tie lock, so that once thedisk (720) passes over the serrations, it is prevented or locked frombeing slid back in the opposite direction. In this way, the disk (720)is slid down into position and locked to sandwich the tissue of thevessel wall and no backsliding of the disk will occur. Thus a firmfixation of the tissue is made for an accurate and cleaner cut. Otherlocking arrangements may be used such as following the disk with afriction tubing (not shown) which is difficult to remove from the shaft(707) and forms a friction stop against which the disk (720) abuts,thereby preventing back sliding or movement of the disk. Other frictionor locking arrangements could be substituted to perform the samefunction, as would be readily apparent to those of ordinary skill in theart.

The centering disk (720) may also function to keep the flexible shaft(707) at the center of the tubular punch (704) and coordinate with thepiercing member to retain and retrieve the tissue cut (734), as shown inFIG. 15B. To that end, the centering disk may have one or more spikes(729) extending out from its surface and adapted to partially pierce orat least frictionally engage the outer wall of the vessel, in order toassist the fixation of the tissue section to be cut. The lengths of thespikes are preferably less than about 5 mm, so as to not completelypierce through the vessel wall and possibly cause blood loss therefrom.Further, the sizing of the spikes are such that they are not long enoughto dislodge plaque, as some lengths may not completely pierce the vesselwall, but would extend far enough into the wall to dislodge plaque,thereby raising the risk of stroke, etc., as described previously. Thespikes are preferably formed of stainless steel or Nitinol. Although thedisk (720) may be formed of Nitinol or stainless steel and the spikesmay then be integrally formed therewith, the disk is preferably formedfrom a polymer such as ABS or polyurethane or other medically acceptablepolymers suitable for this purpose, in which case the spikes may beglued, molded in, threaded or otherwise affixed to the disk.

With regard to the operation procedure, after the physician pushes theshaft to insert the piercing member (708) through the vessel wall, andafter the piercing member is deployed (when using an umbrella-typeactuator), or the barb type piercing member has been rotated, he or shewill twist the punch (704) to create an opening in the vessel wall.Thereafter, the severed tissue (734) is held in place between thepiercing member (708) and the centering disk (720), and retrievedthrough the inner lumen of the punch.

After the retrieval of the severed tissue (734), an occlusion device isinserted in order to prevent blood loss through the opening in thevessel wall. The occlusion device comprises two coaxial cylinders (726,727) as shown in FIG. 15C. The inner cylinder (727), which can be eithersolid or hollow, is slidably located within the outer cylinder (726). Aradially expandable member (730) is attached to an distal end of theinner cylinder (727) and is configured to substantially occlude theopening of the vessel wall once it is inserted into the vessel andextended outside the outer cylinder (726). The radially expandablemember 730 is shown in its fully expanded state in FIG. 15F.

For normal CABG surgery, the outer diameters of the inner and outercylinders are less than about 3 mm and about 6 mm respectively.Preferably, the inner cylinder comprises polymer (polethylenes,polyurethanes, polyamides, polypropylenes) or other acceptable preferredmaterials, or stainless steel) materials such that it is flexible enoughto allow side-to-side movement, and yet has sufficient column strengthfor the physician to push or pull it through.

Disk (720) may have a friction feature or ratchet (e.g., like a tiewrap) or some type of self-locking mechanism against shaft (707) tofrictionally engage or otherwise resist backwards movement of the diskalong the shaft. Thus, once the disk is engaged against the tissue ofthe vessel wall, it sandwiches the tissue cut (734), in cooperation withthe piercing member on the opposite side of the vessel wall.

According to one embodiment of the occlusion device illustrated in FIG.16A, the radially expandable member of the occlusion device comprises aplurality of bristles (702) attached to the distal end of the innercylinder (727). The bristles (702) have memory shapes that flareoutwardly from the distal end of the inner cylinder (727) once therestraint upon the bristles is removed, in order to create a hemostasisarea at the opening of the vessel wall as further described below.

Referring to FIG. 16A, after the punch (704) creates an opening in thevessel wall (714) and the severed tissue is retrieved by the anchormember (728) along with the centering disk (720), the inner cylinder(727) is slid down along with the outer cylinder (726) towards thevessel, with the bristles (702) at its end restrained from expanding bythe outer cylinder. After the bristles are at least substantiallyinserted within the vessel (FIG. 16B), the punch (704) and outercylinder (726) are pulled back from the vessel and withdrawn. As therestraint is removed, the bristles (702) turn into their memory shapeand expand outwardly to form an area of hemostasis at the opening of thevessel wall. Therefore, the vessel does not need to be clamped while ananastomosis is being performed adjacent to the hemostasis area and bloodcan continue to flow within the vessel.

As shown in FIG. 16C, the bristles (702) can be constrained to the innercylinder through a retaining ring (709). The retaining ring (709),binding around a bundle of bristles, is itself attached to the distalend of the inner cylinder (727) by glue or other conventional mechanicalfixing approaches known in the art. Alternatively, the bristles areglued to the inside wall of the inner cylinder (727) as shown in FIG.16D.

Once an area of hemostasis is created with the bristles (702) in place,a graft (712) is brought down over the outer cylinder (726) in place toform an anastomosis (FIG. 16E). A plurality of self-closing fasteners(721), each of which includes a memory coil (724), a deformable wire(not shown, as it is surrounded by memory coil (724)) made of a shapememory alloy, a suture (723) and a needle (722), are used to attach thegraft to the vessel. Such self-closing fasteners are described in detailin copending and commonly assigned U.S. application Ser. No. 09/090,305filed Jun. 3, 1998; WO 99/62406; WO 99/62409; and a copending andcommonly assigned application entitled “Multiple Bias Surgical Fastener”(Attorney's Docket No. 388402001700) which is being filed concurrentlyherewith and therefor does not yet have an application serial number.Each of the aforementioned documents are hereby incorporated byreference herein in their entireties. Such fasteners can be manipulatedby a pair of conventional tweezers known in the art. For grafts andvessels with diameters within the range of 2.5 mm and 6 mm, it ispreferred that twelve fasteners be put in before the bristles areretrieved. The same types of fasteners may be used in closing theanastomosis with the device described above with regard to FIGS.15A-15E.

After the anastomosis is formed, the outer cylinder (726) is broughtdown over the bristles (702) to force them back into a compressed statewithin the outer cylinder (FIG. 16F) and therefore, dissolving thetemporary seal formed at the opening in the vessel wall. Finally, theinner cylinder (727) is retrieved through the outer cylinder (726) alongwith the bristles (FIG. 16G).

One embodiment of the bristles (702) comprises deformable wires madefrom a shape memory alloy. A nickel titanium (Nitinol) based alloy maybe used, for example. The Nitinol may include additional elements whichaffect the yield strength or the temperature at which particularpseudoelastic or shape transformation characteristics occur. The shapememory alloy preferably exhibits pseudoelastic (e.g., superelastic)behavior when deformed at a temperature slightly above itstransformation temperature. At least a portion of the shape memory alloyis converted from its austenitic phase to its martensitic phase when thewire is in its deformed configuration.. As the stress is removed, thematerial undergoes a martensitic to austenitic conversion and springsback to its original undeformed configuration.

When the bristles are positioned within the outer cylinder (726) intheir deformed configuration, a stress is present to maintain thebristles tightly therein. In order for the pseudoelastic bristles toretain sufficient compression force in their undeformed configuration,the bristles should not be stressed past their yield point in theirdeformed configuration to allow complete recovery of the bristles totheir undeformed configuration. It is to be understood that the bristlesmay comprise other materials as well. Depending upon the size of thevessel and the graft, the length of the bristles extending from thedistal end of the inner cylinder (727) can range from about 5 mm toabout 20 mm.

According to another embodiment of the occlusion device as shown in FIG.17A, the radially expandable member comprises an inflatable membrane(800) attached to the distal end of the inner cylinder (727). The innercylinder has an internal lumen so that air can be pumped into themembrane (800) therethrough.

After the opening in the vessel wall is created, the anchor member (708)and the optional centering disk (720) are withdrawn from the vesselalong with the severed tissue. The physician then inserts through thepunch the occlusion member which comprises two generally coaxialcylinders (726, 727) and the membrane (800) in a deflated state. Whenthe membrane (800) is at least substantially within the vessel (FIG.17B), the punch (704) and the outer cylinder (726) are withdrawn and themembrane is inflated to occlude the opening and form an area ofhemostasis.

Each of the fasteners used with this embodiment of the occlusion devicehas two needles (722, 725), one at each end. The fasteners are removablyattached to the membrane and inserted into the vessel together with themembrane. The fasteners (721) can be glued to the membrane or attachedto the membrane through a mechanical fitting such as a sliding or snapfit made of an acceptable material which may be mounted or insert moldedinto the membrane.

Each fastener is so removably attached to the membrane that only oneneedle (722) remains inside the vessel after the membrane (800) isinflated. As the membrane is slightly pulled back by the physician, theneedle inside the vessel pierces through the vessel wall. Such needle(722) is then pulled completely out of the vessel. As the needle (722)is being so pulled, it causes the fastener to separate from the membraneand moves the suture (723) and the memory coil (721) along with it (FIG.17C). Meanwhile, a graft (712) is brought down to be attached to thevessel. The other needle (725) that has not been inserted into thevessel is then manipulated to pierce through the graft. Such needle(725) leads the suture (723) and the memory coil (721) through thegraft. After both ends of the memory coil are outside the graft and thevessel, the memory coil self closes upon a release of the lockingmechanism and both the suture (723) and the needles (722, 725) arereleased and removed (FIG. 17D). When sufficient number of fasteners aresecurely placed between the graft and the vessel, an anastomosis issuccessfully performed. The membrane is then deflated and moved outalong with the cylinder (727) through the graft.

FIGS. 17E-17K are detailed drawings of a fastener (721) and portionsthereof, which may be used in connecting the graft (712) to the vessel,as described above and below. Although described in conjunction with theembodiment of FIG. 17A, it is noted that fasteners of this type may beused with any of the other embodiments of the present inventiondescribed herein.

Referring to FIG. 17E, a tissue connector assembly (721) having multiplepiercing members is shown. In a preferred embodiment, two piercingmembers (722) and (725), each of which may comprise a needle, arereleasably coupled to a fastener. The coupling between the flexiblemember (18, 19), and thus, the piercing member (722, 725) and thefastener (721) may be constructed to actuate closure of the fastener(721) upon release of the flexible member (18, 19) (or piercing member)(722, 725). For example, the coupling may hold a compression spring (26)(which is positioned around a fastener) in a compressed state to bracethe fastener open and releasably lock or secure the fastener to theflexible member (or piercing member).

As shown in FIG. 17E, a tissue connector assembly (721) which generallycomprises tissue piercing or penetrating members (722) and (725),flexible members (18) and (19), and a fastener (20) (e.g., a surgicalslip) is shown. A restraining device, generally indicated at (24) andcomprising a spring (or coil) (26) and a locking device (or couplingmember) generally indicated at (28) and (29), are connected to fastener(20) for holding the fastener in a deformed or open configuration aswill be further described below. Penetrating or piercing member (725)may be made in accordance with the description provided above inconnection with penetrating member (721), and, thus may, for example, bein the form of a needle (such as a 7-0 or 8-0 needle) having a sharppointed tip (31) at its distal end for penetrating tissue. Members (722)and (725) are preferably the same but may differ from one another.Flexible members (18) and (19) and tapered portions (2) and (3) also mayhave the same construction.

Referring to FIG. 17F, a release mechanism (28 a) also may be used asrelease mechanism (29) to releasably couple the other end of thefastener to another flexible member such as flexible member (19), whichin turn, in coupled to a needle such as needle (725) as shown in FIG.17E. In this arrangement, a member or stopper (115), which may beannular, is secured to the other end of the fastener or wire (34) toprevent enlarged portion (36) from passing through the compressionspring upon release from release mechanism (28 a).

FIGS. 17G and 17H illustrate a synchronized fastener release system. Onerelease mechanism may correspond to mechanism (28 a). At the other endof the fastener or wire (34), a release mechanism which responds to thecompressive state of coil (26) and releases the fastener or wire (34)upon release of compressive forces on the coil is shown and generallydesignated with reference numeral (29 a). Referring to FIGS. 17G and17H, release mechanism (29 a) comprises two members (121), each having arecess (122) formed therein and arranged to form chamber (124) whenmembers (121) are aligned as shown in FIG. 17G. Recesses (122) areconfigured to retain enlarged portions (36), which are shown with acylindrical configuration, but may have a spherical or other suitableshape for operatively associating with a suitably configured chamber.Further, members (121) may have semicircular transverse cross sectionsor some other combination of transverse shapes that can collectivelyprovide the desired chamber to retain enlarged portion (36). The numberof members (121) also may vary as would be apparent to one of ordinaryskill.

Release mechanism members (121) have tapered ends (126), which areconfigured for positioning between coil (26) and fastener wire (34) asshown in FIG. 17G. When tapered ends (126) are so positioned and coil(26) is in a compressed state, coil (26) holds tapered ends (126), whichare normally biased away from each other, sufficiently together toretain enlarged portion (36) within chamber (124). When releasemechanism (28 a) is actuated (e.g., radially compressed) to releaseenlarged portion (36) of fastener wire (34), coil (26) assumes itsrelaxed state, thereby releasing tapered ends (126) of release mechanism(29 a) from the coil and allowing the tapered ends to radially expandand release enlarged portion (36) of fastener wire (34). Accordingly,both needles and flexible members may be decoupled from the fastenerwhen release mechanism (28 a) is actuated. Further description of therelease mechanisms described above are included in copending, commonlyassigned application Ser. Nos. 09/259,705 and 09/260,623, entitled“Tissue Connector Apparatus with Cable Release” and “Tissue ConnectorApparatus and Methods”, respectively, both of which were filed on Mar.1, 1999, and both of which are incorporated by reference thereto, hereinin their entireties. Additionally, copending and commonly assignedapplication entitled “Multiple Bias Surgical Fastener” (Attorney'sDocket No. 388402001700, which is being filed concurrently herewith andtherefor does not yet have an application serial number, and which wasincorporated by reference above) describes additional double needlefasteners, including, for example, a multiple bias fastener havingdouble needles, which may be used in the present examples.

FIGS. 17I-17K show another synchronized fastener system which is thesame as the system described with reference to FIGS. 17F-17H with theexception of release mechanism (29 b) and the cooperating portion of thefastener or wire (34) being substituted for release mechanism (29 a). Inthis embodiment, a member or stopper (115), which may be annular, isslidably coupled to fastener wire (34). Member (115) is configured toresist passage of coil (26) thereover. Accordingly, member (115) mayhave an outer diameter slightly greater than at least the portion of thecoil adjacent thereto. A tapered or frustoconical member (3′) is securedto an end of fastener wire (34), which need not include an enlargedportion. Member (3′) is the same as member (3) with the exception thatmember (3′) has a channel (134) for receiving flexible member or suture(19), as shown in FIGS. 17I and K. Channel (134) extends radiallyOutward from bore (132), which is formed through member (3′), forreceiving the fastener or wire (34).

Flexible member (19) is threaded through channel (134) and betweentapered member (3′) and annular member (115). When coil (26) is in acompressed state as shown in FIG. 17I, the coil urges member (115)toward tapered member (3′) and compresses flexible member (19)therebetween. In this manner, flexible member (19) is secured to thefastener or wire (34). When release mechanism (28 c) is actuated (e.g.,radially compressed) to release enlarged portion (38) of the fastener orwire (34), coil (26) assumes its relaxed state so that annular member(115) may slide away from tapered member (3′) and release flexiblemember (19). Accordingly, both needles and flexible members may beremoved from the fastener when release mechanism (28 c) is actuated.Although a metal flexible member may be used, a polymeric flexiblemember may be preferred.

As shown in FIG. 17I, for example, coil (26) comprises a helical wireforming a plurality of loops which define a longitudinal opening forreceiving a shape memory alloy wire (34). Coil (26) may be formed from aplatinum alloy wire having a cross-sectional diameter of approximately0.0005-0.005 inch, for example. The helical wire may have othercross-sectional shapes and be formed of different materials, such asNitinol, for example. Coil (26) is preferably sized so that when in itsfree (uncompressed state) it extends the length of wire (34) with oneend adjacent an enlarged portion (36 or 38) at the proximal end of thewire and the other end adjacent enlarged portion (38 or 36) at thedistal end of the wire. It is to be understood that the coil may notextend the full length of the wire. For example, a flange or similardevice may be provided on an intermediate portion of wire (34) to limitmovement of the coil along the length of the wire.

When coil (26) is in its free state (with the wire in its undeformedconfiguration), loops of the coil are generally spaced from one anotherand do not exert any significant force on the wire (34). When the coil(26) is compressed (with the wire (34) in its deformed configuration),loops of the coil on the inner portion of the coil are squeezed togetherwith a tight pitch so that the loops are contiguous with one anotherwhile loops on the outer portion of the coil are spaced from oneanother. This is due to the compressed inner arc length of coil (26) andthe expanded outer arc length of the coil. The compression of the loopson the inner portion of coil (26) exerts a force on the inner side ofwire (34) which forces the wire to spread open (i.e., tends tostraighten the wire from its closed configuration to its openconfiguration).

According to a further aspect of the occlusion device as shown in FIGS.18A-18B, a cylindrical sheath (850) is used to protect the membrane(800) from being punctured by the needles (722, 725), if the fasteners(721) are not attached to the membrane (800) and need to be insertedafter the membrane is inflated: In order to be sufficiently flexible andyet to have the necessary tensile strength, the membrane (800) (see FIG.18A, for example) is preferably made of polymeric materials such aspolyethylene terephthalate, polyethylene and polyurethane. It ispreferable that the membrane be compliant, yet tough enough to allowmanipulation without failure. The membrane is fixed (by gluing orsimilar method) to the inner cylinder (727) at its proximal end and thesheath (850) is axially fixed to the membrane (800).

In order to facilitate the expansion of the sheath (850) with themembrane to occlude the opening in the vessel wall, the sheath (850)overlaps itself in a roll-up fashion, as shown in FIG. 18C. The sheath(850) is expanded and unrolled by the expansion of the membrane (800).The sheath (850) unrolls so as to cover the circumference of theexpanded membrane (800) as it expands, so as to fully cover the membrane(800) in its expanded position (FIG. 18B).

After occlusion of the opening by the membrane (800) and the sheath(850), the punch (704) and the outer cylinder (726) can be withdrawn anda graft (712) is slid down (FIG. 18D). A plurality of fasteners (721)are inserted to attach the graft to the vessel (FIG. 18E). As the finalstep, the membrane (800) is then deflated and withdrawn along with thesheath (850).

The sheath (850) may be made of superelastic materials such as Nitinolor stainless steel, etc. as described above. Alternatively, the sheathmay be made of polymeric materials, e.g., thin polycarbonate,polyurethane, etc. In order to facilitate the expansion of the sheathwith the membrane, it is preferable that the sheath has a wall thicknessof less than about 0.5 mm.

According to another further aspect of the occlusion device asillustrated in FIG. 19A, the radially expandable member comprises aplurality of expansion members (854), preferably made from asuperelastic material, e.g. Nitinol, attached to the distal end of theinner cylinder (727). Solid attachment may be achieved by use of gluematerials or by welding or fusion of the two. FIG. 19B illustrates theradially expandable member in a compressed state within the outercylinder (726).

Each expansion member is attached to its adjacent members by a membrane(860). The membrane is held to the expansion member by e.g., glue,sandwich construction or other equivalent known techniques. Theexpansion members are arranged in a radially projecting pattern from thedistal end of the inner cylinder (726) so that they can expand outwardlyand form an umbrella when they exit the outer cylinder (726) (FIG. 18B).This creates an occlusion of the vessel wall opening. The expansionmembers are curved to present a convex surface so as to better withstandthe pressure inserted by the blood flow.

The membrane (860) can be made in any suitable material which can blockflow of fluid, particularly blood, therethrough. In choosing thematerial for the membrane, factors such as strength, flexibility, orbonding to the expansion elements should be considered. For example, themembrane may comprise latex, silicone, PET, etc.

In another example of the present invention shown in FIGS. 20A-20F, anocclusion device is provided with an adapter (794) that temporarilyholds a plurality of needles (725′) to be driven through the wall of thevessel (714). The procedure for preparing the opening in the wall of thevessel (714) is essentially the same as that described above with regardto FIGS. 15A and 15B, for example, with the exception that the tube ofthe cutting member or punch (704′) is much shorter than the tube of thecutting member or punch (704), and is adapted to receive an adapter,preferably a tubular adapter (740) as shown in FIG. 20A. The cuttingmember (704′) is preferably made of a biocompatible metal such asstainless steel, Nitinol, titanium alloys, or the like, much the same asthe cutting member (704), and similarly has a distal cutting edge.

The adapter (740), on the other hand, is preferably made ofbiocompatible plastics, such as ABS, polyurethanes, polycarbonates, orother medically compatible and acceptable polymers, for ease and lessexpense in manufacturing, although the adapter (740) may also be formedof the same metals used in making the cutting member (704′). The adapter(740) has about the same outside diameter as the tube of the cuttingmember (704′), or if slightly larger in diameter, is tapered (742) so asto facilitate the insertability of the adapter through the opening inthe vessel (714). The walls of the adapter (740) are provided with boresor wells (744) that are dimensioned to snugly hold needles (725′)therein. The wells (744) may be mechanically formed in the adapter (740)as by boring, melting, electrodischarge machining, etc., or may bemolded in during the formation of the adapter, for example. The wells(744) are formed so as to fit closely enough with the needles (725′) soas to maintain the needles at the desired angular orientation withrespect to the longitudinal axis of the adapter (740), but not so tightas to form an impediment to their removal by hand or with a hand tool atthe appropriate time during the procedure. The adapter orients theneedles at an angle of between about 10 and 45 degrees. In one preferredexample, the angle is about 30 degrees.

After formation of the opening in the vessel (714) wall and removal ofthe tissue plug (734) using anchor member (728) and disk (720), as shownin FIG. 20A and described above, the adapter (740) is driven to insertthe cutting member (704′) further and entirely within the vessel (714)and to insert a portion of the adapter (740) into the vessel (714), tothe extent that the needles (725′) are within the vessel (114) andpositioned to pierce the inner wall of the vessel (714), as shown inFIG. 20B. The needles (725′) flex inwardly and approach the wall of theadapter as they pass through the opening in the vessel, and then resumetheir previous orientation once they have completed cleared the wall ofthe vessel (714) as shown in FIG. 20B. The adapter (740) preferablyholds four to eight needles (725′) which are equidistantly spacedcircumferentially around the adapter, although certainly more thaneight, and likely less than four needles could be successfully used, aswould be apparent to one of ordinary skill in the art, after reading thepresent disclosure.

In this embodiment, the needles (725′) preferably, although notnecessarily, differ from needles (721) in that the needles (125′) arepreferably substantially straight, while needles (721) are preferablycurved. Further, this embodiment preferably, although not necessarily,uses two-stage release fasteners (821) for sequentially fastening theanastomosis as further described below.

Turning to FIG. 21A, a partial schematic view of a two-stage releasefastener (821) is shown. The fastener (821) includes a deformable wire(825) made of a shape memory alloy, such as that described above withregard to fasteners (721). The deformable wire preferably includesenlarged portions (36) at opposite ends and which are substantiallyidentical to one another. Retainers (836) are swedged or welded onto thewire (825) after compression of coils (724′) as described further below.

Coils (724′) are substantially the same as any of the coils (724) or(26) described above with the exception of being shorter to allow serialplacement of two coils (724′) on a single wire (825) to enable separateand independent actuation and closing of opposite sides of the fastener(721). Release mechanisms (28 a), which are preferably, but notnecessarily the same, are releasably coupled to the respective enlargedends (36) at opposite ends of the wire (825), and are, in turn coupledto the needles (722) and (725) by flexible members (18) and (19)respectively. The release mechanisms (28 a) in this embodiment arepreferably cable type release mechanisms, as described in copendingapplication Ser. No. 09/259,705 entitled “Tissue Connector Apparatuswith Cable Release”, and as shown above in FIG. 17F, for example,although other release mechanisms such as described herein and in thosedocuments incorporated by reference can also be used.

Assembly of the fastener (821) into the open position as shown in FIG.21A is performed by first forming the wire (825) to set its shape memoryand to form an enlarged portion (36) at one end thereof, preferably byan electric discharge technique. Other methods of forming the enlargedportion, as well as methods of setting the memory shape of the wire(825) are described in detail in commonly assigned application entitled“Multiple Bias Surgical Fastener” (Attorney's Docket No. 388402001700)which is being filed concurrently herewith and therefor does not yethave an application serial number, and in copending and commonlyassigned application Ser. No. 09/090,305.

A first coil (724′) is next slid over the wire (825) and an end of thecoil (724′) is abutted against or placed adjacent to the enlargedportion (36). Next, a first retainer (836) is slid over the wire (825)and abutted against the opposite end of the coil (724′), after which asecond retainer (836) is slid over the wire and placed adjacent thefirst retainer (836). A second coil (724′) is then slid over the wire(825) and a first end is abutted against the second retainer (836),while the second end of the second coil (724′) is used to determinewhere the wire (825) is cut to length. Generally, the wire (825) is cutso that it extends far enough, so that once the enlarged portion isformed at the end, the first and second portions are symmetric.

After cutting to length, the second end of the wire (825) is formed intoan enlarged portion (836), preferably by electrodischarge. A firstrelease mechanism (28 a) is next fitted over the first enlarged portion(36), preferably according to the techniques described in copendingapplication Ser. No. 09/259,705 with regard to the cable release. Thefirst retainer (836) is then slid against the coil (724′) to compress itto a position that forces the first side of the fastener into its openconfiguration. The first retainer (836) is then swedged at its locationto maintain the first portion of the fastener in the open position.Although swedging is preferred, welding or other equivalent methods offixation may also be used to fix the retainer in place.

Likewise, a second release mechanism (28 a) is fitted over the secondenlarged portion (36), and the second retainer (836) is then slidagainst the second coil (724′) to compress it to a position that forcesthe second side of the fastener into its open configuration. The secondretainer (836) is then swedged at its location to maintain the secondportion of the fastener in the open position, which results in theentire fastener (821) now being in its open position, as shown in FIG.21A. The placement and fixation of the retainers (836) results in theformation of a gap (838) therebetween.

Actuation of the first release mechanism (28 a) is by squeezing orcompression of a portion of the mechanism, which causes it to open,thereby releasing the enlarged portion (36). This, in turn allows are-expansion of the coil (724′) thereby relieving the opening stressesagainst the first portion of the wire (825), thereby allowing the memoryset of the wire (825) (and the memory set of the coil (724′) when adouble memory configuration is used) to return the first portion of thewire (825) to the closed or memory position, as shown in FIG. 21B.

Actuation of the second release mechanism (28 a) is performedindependently of the first release mechanism, and therefor allows anindependent closing of the second portion of the fastener (821), asshown in FIG. 21C. The mechanism for closing the second portion ispreferably the same as that described above for closing of the firstportion.

Returning to FIG. 20B, the adapter, and thus the entire assembly, isnext pulled back some so as to pierce the wall of the vessel (714) witheach of the needles (725′). Once the needles have fully penetrated thevessel wall and protrude through the outside wall of the vessel, theadapter is maintained in its position, and the needles (725′) are pulledall the way through the wall of the vessel (714), one at a time, toposition the fasteners (821), an example of which is shown in FIG. 20C.A flexible sealing member, such as radially expandable member (730), forexample, or cylindrical sheath (850) and membrane (800), or acylindrical restraining sheath (900) and expandable, flexible sealingmember (950) (FIG. 20C), or other occluding member as described herein,is then inserted. The restraining sheath (950) may be formed of the samematerials as described above with regard to sheath (850) and theflexible sealing member may be formed from the same materials asdescribed above with regard to radially expandable member (730) ormembrane (860). The straight needles (725′) and flexible members (19)are then removed from the fasteners (821) by releasing the releasemechanisms (28 a) attached thereto, from the respective enlargedportions (36) as described above. This closes the first portion of eachfastener (821) thereby fixing them in position in the location of thevessel wall, as exemplified in FIG. 20D.

Once the fasteners (821) have been fixed into the wall of the vessel(714), the flexible sealing member (900) is expanded to establish theocclusion by removing the restraining sheath (950) from its restrainingposition, as shown in FIG. 20D. The tube cutter assembly, including thecutting member or punch (704′) and the adapter (740) are then withdrawnfrom the vessel, as shown in FIG. 20D, and removed from overlying therestraining sheath (950).

After removal of the tube cutter assembly, a graft (712) is positionedover the restraining sheath (950) and into position at the anastomosissite as shown in FIG. 20E. The needles (722) are next used to pierce thewalls of the graft (712) from inside to outside, and then pulled throughentirely to position the second portions of the fasteners (821) in thewall of the graft (712). Once the fasteners are positioned, the needles(722) and flexible members (18) are removed from the respectivefasteners (821) to close the second portions of the fasteners (821) inthe same manner as described above with regard to closing of the firstportions of the fasteners (821).

After all of the fasteners (821) have been fully closed to complete theapproximation and anastomosis of the vessel (714) and graft (712), therestraining sheath (950) is slid back down over the flexible sealingmember (900) to compress it and surround it as shown in FIG. 20F. Therestraining sheath (950), together with the flexible sealing member(900) therein, are then pulled away together so as to be removed fromthe anastomosis site and the graft. This completes the anastomosisprocedure.

The above is a detailed description of particular embodiments of theinvention. It is recognized that departures from the disclosedembodiments may be made within the scope of the invention and thatobvious modifications will occur to a person skilled in the art. Thefull scope of the invention is set out in the claims that follow andtheir equivalents. Accordingly, the claims and specification should notbe construed to unduly narrow the full scope of protection to which theinvention is entitled.

1. An anastomosis apparatus comprising: a tubular member having an endwith an edge adapted to form an opening in a vessel wall; and anocclusion member slidably coupled to the tubular member and adapted tosubstantially occlude said opening in the vessel wall to form an area ofhemostasis.
 2. The anastomosis apparatus of claim 1 wherein theocclusion member is a cannula having a cross-section adapted tosubstantially occlude said opening in the vessel wall.
 3. Theanastomosis apparatus of claim 1 wherein the occlusion member comprisesa first and a second generally coaxial cylinders, and a radiallyexpandable member attached to a distal end of said first cylinder tosubstantially occlude said opening in the vessel wall, said firstcylinder being slidably positioned within said second cylinder.
 4. Theanastomosis apparatus of claim 3 wherein the radially expandable membercomprises a plurality of bristles extending from said distal end of saidfirst cylinder, said bristles having memory shapes that flare outwardlyfrom said distal end of said first cylinder.
 5. The radially expandablemember of claim 4 wherein the bristles comprise nickel-titanium alloy.6. The radially expandable member of claim 4 wherein the lengths of thebristles are less than 20 mm.
 7. The radially expandable member of claim4 wherein the first cylinder is hollow and the bristles are glued,attached, or otherwise fixed to an inside wall of the first cylinder. 8.The radially expandable member of claim 4 wherein the bristles arerestrained by a ring attached to said distal end of the first cylinder.9. The occlusion member of claim 4 wherein the first cylinder has anouter diameter of less than 8 mm.
 10. The occlusion member of claim 4wherein the first cylinder comprises polymeric material and/or stainlesssteel or other metallic material.
 11. The occlusion member of claim 4wherein the second cylinder has an outer diameter of less than 15 mm.12. The occlusion member of claim 4 wherein the second cylindercomprises polymeric material and/or stainless steel, or other metallicmaterial.
 13. The anastomosis apparatus of claim 3 wherein the radiallyexpandable member comprises a radially expandable membrane.
 14. Theradially expandable member of claim 13 further comprising a plurality offasteners removably attached to the membrane, said fasteners beingadapted to attach a graft to the vessel wall.
 15. The radiallyexpandable member of claim 14 wherein the fasteners are removablyattached to the membrane by glue.
 16. The radially expandable member ofclaim 14 wherein the fasteners are mechanically removably attached tothe membrane.
 17. The radially expandable member of claim 13 wherein themembrane comprises materials selected from the group consisting of:polyethylene terephthalate, polyethylene and polyurethane.
 18. Theradially expandable member of claim 13 further comprising a generallycylindrical sheath located coaxially outside the membrane, said sheathbeing radially expandable with the membrane.
 19. The radially expandablemember of claim 18 wherein the sheath comprises nickel-titanium alloy.20. The radially expandable member of claim 18 wherein the sheathcomprises polymeric materials.
 21. The radially expandable member ofclaim 18 wherein the sheath has a wall thickness of less than about 0.5mm.
 22. The radially expandable member of claim 18 wherein the sheathoverlaps itself in a roll-up fashion.
 23. The anastomosis apparatus ofclaim 3 wherein the radially expandable member comprises a plurality ofexpansion members attached to said distal end of said first cylinder,said expansion members supporting a membrane therebetween and beingfoldable from an expanded position to a collapsed position.
 24. Theradially expandable member of claim 23 wherein the expansion membersform a substantially convex surface in said expanded position.
 25. Theradially expandable member of claim 23 wherein the membrane isdimensioned to block the flow of blood through the opening in the vesselwall.
 26. The radially expandable member of claim 23 wherein theexpansion members comprise superelastic or shape memory materials. 27.The radially expandable member of claim 23 wherein the membranecomprises a medically compatible polymer.
 28. The anastomosis apparatusof claim 3 wherein the radially expandable member comprises a membraneattached to said distal end of said first cylinder, said membrane beingradially expandable from a collapsed position to an expanded position.29. The radially expandable member of claim 30 wherein the membraneforms a substantially convex surface in said expanded position.
 30. Theradially expandable member of claim 30 wherein the membrane isdimensioned to block the flow of blood through the opening in the vesselwall.
 31. The radially expandable member of claim 30 wherein themembrane comprises materials selected from the group consisting ofpolyethylene terephthalate, polyethylene and polyurethane.
 32. Theanastomosis apparatus of claim 1, further comprising an adaptercoaxially mounted to said tubular member and adapted to pass saidocclusion member therethrough.
 33. The anastomosis apparatus of claim32, said adapter further comprising wells adapted to hold needles in apredetermined orientation.
 34. The anastomosis apparatus of claim 32,further comprising needles mounted in wells in said adapter, said wellsholding said needles in an orientation adapted to pierce a vessel wallfrom the inside out.
 35. The anastomosis apparatus of claim 34, furthercomprising fasteners connected with said needles, respectively, saidfasteners being adapted to fix a graft to a vessel.
 36. The anastomosisapparatus of claim 35, each of said fasteners comprising a clip movablebetween an open and a closed configuration and having a memory biased tosaid closed configuration, said clip having a first portion including afirst end portion and a second portion including a second end portion; afirst mechanical restraint coupled to said first portion of said clipand adapted to bias said first portion toward said open configuration;and a second mechanical restraint coupled to said second portion of saidclip and adapted to bias said second portion toward said openconfiguration.
 37. The anastomosis apparatus of claim 36, each of saidfasteners further comprising a first release mechanism releasably fixedto said first end portion and adapted to release the bias of said firstmechanical restraint against said first portion upon release from saidfirst end portion.
 38. The anastomosis apparatus of claim 37, each ofsaid fasteners further comprising a flexible member interconnecting oneof said needles with said first release mechanism.
 39. The anastomosisapparatus of claim 37, each of said fasteners further comprising asecond release mechanism releasably fixed to said second end portion andadapted to release the bias of said second mechanical restraint againstsaid second portion upon release from said second end portion.
 40. Theanastomosis apparatus of claim 39, each of said fasteners furthercomprising a second needle releasably fixed to said second releasemechanism.
 41. The anastomosis apparatus of claim 40, each of saidfasteners further comprising a second flexible member interconnectingsaid second needle with said second release mechanism.
 42. Ananastomosis system comprising: a tubular member having an end with anedge adapted to form an opening in a vessel wall; and an occlusionmember slidably coupled to the tubular member and adapted tosubstantially occlude said opening in the vessel wall to form an area ofhemostasis.
 43. The anastomosis system of claim 42 further comprising ananchor member adapted to hold said vessel wall in place while thetubular member is forming said opening in said vessel wall, said anchormember being slidably coupled to the tubular member.
 44. The anastomosissystem of claim 43 wherein the anchor member comprises a shaft and apiercing member extending from a distal end of said shaft, said piercingmember being adapted to pierce the vessel wall.
 45. The anchor member ofclaim 44 wherein said shaft comprises a flexible polymeric material. 46.The anchor member of claim 44 wherein the shaft has a diameter of lessthan 3 mm.
 47. The anchor member of claim 44 wherein the piercing memberhas a tapered end.
 48. The anchor member of claim 44 wherein thepiercing member has a pointed end.
 49. The anastomosis system of claim43 further comprising a generally circular centering disk slidablymovable along the piercing member.
 50. The anastomosis system of claim49 wherein the centering disk is made from a medically acceptablepolymer.
 51. The anastomosis system of claim 49 wherein said centeringdisk comprises ABS or polyurethane.
 52. The anastomosis system of claim49 wherein the centering disk comprises one or more spikes extendingfrom a surface of the centering disk proximal of the vessel wall. 53.The centering disk of claim 52 wherein said one or more spikes compriseNitinol.
 54. The centering disk of claim 52 wherein said one or morespikes have lengths of less than about 5 mm.
 55. A cannula comprising abody member forming a lumen and a piercing member extending from saidbody member, said piercing member having a generally cylindrical edgeadapted to cut tissue and said piercing member forming a cavity adaptedto receive the tissue.
 56. The cannula of claim 55 wherein saidcylindrical edge is pointed.
 57. The cannula of claim 55 furtherincluding a rod extending through said lumen, said rod having a pointedmember extending therefrom.
 58. The cannula of claim 57 wherein saidpointed member includes a portion adjacent to said cylindrical edge,said pointed head portion having diameter greater than the innerdiameter of said cylindrical edge.
 59. A trocar comprising a body havinga proximal portion, a distal portion, and a passageway extending betweensaid proximal and distal portions, said passageway changing in dimensionalong a longitudinal portion thereof.
 60. The trocar of claim 59 furtherincluding a seal disposed within said passageway.
 61. A surgicalfastener cartridge comprising: a first tubular member; a second tubularmember slidably coupled to said first tubular member; and at least onesurgical fastener having one end engaging said first tubular member anda second end engaging said second tubular member.
 62. The cartridge ofclaim 61 wherein said surgical fastener has first and second shapes andsaid tubular member bias said fastener to said second shape.
 63. Thecartridge of claim 62 including a rod disposed in said secondcylindrical member and urging said second end of said fastener againstsaid second tubular members.
 64. A method for performing an anastomosiswhile maintaining blood flow within a vessel comprising: positioning acannula so that it extends through a vessel wall; attaching a graft tothe vessel wall adjacent to said cannula while said cannula extendsthrough said vessel wall; and removing the cannula.
 65. The method ofclaim 64 wherein the cannula is positioned in the vessel wall from theinterior of the vessel.
 66. A method for performing an anastomosis on avessel wall while maintaining blood flow within the vessel comprising:forming an opening in the blood vessel; inserting an occluding memberinto the opening cut into the vessel, thereby occluding the opening; andanastomosing a graft to the vessel at the opening.
 67. The method ofclaim 66, wherein said forming an opening comprises: piercing the vesselwall with an anchor member; and cutting the opening in the vessel wallaround the anchor member with a cutting tool.
 68. The method of claim67, further comprising removing a tissue plug produced by said cutting,prior to said inserting an occluding member.
 69. The method of claim 67,wherein said inserting comprises inserting the occluding member into theopening cut into the vessel while the cutting tool is still in theopening.
 70. The method of claim 69, further comprising withdrawing thecutting tool to allow the occluding member to expand against theperiphery of the opening, thereby occluding it.
 71. The method of claim70, further comprising placing a graft over the occluding member and inalignment with the opening, prior to said anastomosing.
 72. The methodof claim 67, further comprising sliding a generally circular centeringdisk along the anchor member onto the vessel wall, prior to saidcutting, thereby clamping vessel wall tissue between the centering diskand an end portion of the anchoring member.
 73. The method of claim 72,further comprising removing the tissue plug in a clamped configurationbetween the centering disk and anchoring member.
 74. The method of claim66, wherein said anastomosing comprises fastening walls of the graft andvessel together using fasteners.
 75. The method of claim 74, whereinsaid fastening is performed with self closing fasteners.
 76. The methodof claim 66, wherein the occluding member includes fasteners attachedthereto, said method further comprising pulling back said occludingmember slightly, after expanding to occlude, thereby piercing the vesselwall with needles attached to said fasteners.
 77. The method of claim76, further comprising grasping the needles and pulling them entirelythrough the vessel wall, thereby positioning the fasteners forperforming the anastomosis and separating them from the occludingmember.
 78. The method of claim 77, wherein the fasteners each have asecond needle at an end opposite the location of the needles used topierce the vessel wall, said anastomosing further comprising piercingthe graft with the second needles and securing the graft and the vesseltogether by closing the fasteners upon them.
 79. The method of claim 67,wherein an adapter is mounted on the cutting tool, the adapter retaininga plurality of needles therein which are propositioned for piercing thevessel from the inside out, said method further comprising inserting thecutting tool and adapter into the vessel, prior to said inserting anoccluding member, so as to position the needles against the inner wallof the vessel, and pulling back the adapter and cutting tool slightly topierce the vessel wall with the needles; grasping the needles andpulling them all the way through the vessel and thereby also removingthem from the adapter.
 80. The method of claim 79, wherein the needlesare connected to two-stage release fasteners having independentlyclosable first and second portions, the needles being connected byflexible members to respective first portions of the fasteners, saidmethod further comprising removing the needles and flexible members fromthe fasteners, after insertion of the occluding member, thereby closingthe first portions of the fasteners and fixing the fasteners to the wallof the vessel.
 81. The method of claim 80, wherein the fasteners eachhave a second needle connected to an end portion of the second portionthereof by a second flexible member, said anastomosing furthercomprising piercing the graft with the second needles and securing thegraft and the vessel together by removing the second needles and secondflexible members from the second portions of the fasteners, therebyclosing the second portions of the fasteners on the graft and fixing thewalls of the vessel and the graft in approximation.
 82. An occlusiondevice comprising first and a second generally coaxial cylinders, thefirst cylinder being slidably positioned within the second cylinder andhaving a plurality of bristles extending from a distal end of said firstcylinder, said bristles having memory shapes that flare outwardly fromsaid distal end of the first cylinder.
 83. The occlusion device of claim82, wherein the bristles are made of super-elastic materials comprisingnickel-titanium alloy.
 84. The occlusion device of claim 82, wherein thelengths of the bristles extending from the distal end of the firstcylinder are of less than about 5 mm.
 85. The occlusion device of claim82, wherein the bristles are fixed to the inside wall of the firstcylinder.
 86. The occlusion device of claim 82, wherein the bristles arerestrained by a ring attached to the distal end of the first cylinder.87. The occlusion device of claim 82, wherein the first cylinder has anouter diameter of less than about 3 mm.
 88. The occlusion device ofclaim 82, wherein the first cylinder has a wall thickness of less thanabout 0.5 mm.
 89. The occlusion device of claim 82, wherein the firstcylinder comprises a medically compatible polymeric material.
 90. Theocclusion device of claim 82, wherein the second cylinder has a wallthickness of less than about 0.5 mm.
 91. The occlusion device of claim82, wherein the second cylinder comprises a medically compatiblepolymeric material.
 92. An occlusion device comprising a radiallyexpandable membrane and a plurality of fasteners removably attached tothe membrane, said fasteners being adapted to attach a graft onto avessel.
 93. The occlusion device of claim 92, wherein the fasteners areattached to the membrane by glue.
 94. The occlusion device of claim 92,wherein the fasteners are attached to the membrane through a mechanicalfitting mechanism.
 95. The occlusion device of claim 92, wherein themembrane comprises a medically compatible polymer.
 96. An occlusiondevice comprises a radially expandable membrane and a generallycylindrical sheath located coaxially outside the membrane, said sheathbeing radially expandable with the membrane.
 97. The occlusion device ofclaim 96, wherein the sheath comprises nickel-titanium alloy.
 98. Theocclusion device of claim 96, wherein the sheath comprises at least onepolymeric material.
 99. The occlusion device of claim 96, wherein thesheath has a wall thickness of less than about 0.5 mm.
 100. Theocclusion device of claim 96, wherein the sheath overlaps itself in aroll-up fashion, the overlap being greater in the unexpandedconfiguration and lesser in an expanded configuration.
 101. An occlusiondevice comprising first and a second generally coaxial cylinders and aplurality of expansion members attached to a distal end of the firstcylinder, said expansion members supporting a membrane therebetween andbeing foldable from a collapsed position and an expanded position, andsaid first cylinder being slidably positioned within said secondcylinder.
 102. The occlusion device of claim 101, wherein the expansionmembers form a substantially convex surface in said expanded position.103. The occlusion device of claim 101, wherein the membrane isdimensioned to block the flow of blood through an opening in a vesselwall.
 104. The occlusion device of claim 101, wherein the expansionmembers comprise superelastic material.
 105. The radially expandablemember of claim 96 wherein the membrane comprises at least one medicallycompatible polymeric material.
 106. An occlusion device comprising firstand second generally coaxial cylinders, and a membrane attached to adistal end of said first cylinder, said membrane being radiallyexpandable from a collapsed position to an expanded position.
 107. Theocclusion device of claim 102, wherein the membrane forms asubstantially convex surface in said expanded position.
 108. Theocclusion device of claim 106, wherein the membrane is dimensioned toblock the flow of blood through the opening in the vessel wall.
 109. Theocclusion device of claim 106, wherein the membrane comprises at leastone material selected from the group consisting of polyethyleneterephthalate, polyethylene and polyurethane.
 110. An occlusion devicecomprising a radially expandable member expandable from a relativelycompressed smaller external dimension to a radially expanded, relativelylarger external dimension, said radially expanded member fixed to an endof an elongated member; and a cylindrical restrictor adapted to passover said elongated member and said radially expandable member, therebycompressing said radially expandable member so that it assumes saidrelatively compressed smaller external dimension.
 111. The occlusiondevice of claim 110, wherein said restrictor is adapted to slide off ofsaid radially expandable member, thereby allowing said radiallyexpandable member to expand.
 112. A dual-stage release fastenercomprising: a clip movable between an open and a closed configurationand having a memory biased to said closed configuration, said cliphaving a first portion including a first end portion and a secondportion including a second end portion; a first mechanical restraintcoupled to said first portion of said clip and adapted to bias saidfirst portion toward said open configuration; and a second mechanicalrestraint coupled to said second portion of said clip and adapted tobias said second portion toward said open configuration.
 113. Thefastener of claim 112, wherein said first and second mechanicalrestraints are independently manipulatable to allow independent closureof said first and second portions of said clip.
 114. The fastener ofclaim 112, further comprising an enlarged first end portion on saidfirst portion and an enlarged second end portion on said second portion.115. The fastener of claim 114, further comprising first and secondretainers fixed on said clip and abutting said first and secondmechanical restraints respectively.
 116. The fastener of claim 115,further comprising first and second release mechanisms releasablyfastened to said first and second enlarged end portions respectively,said release mechanisms being independently operable to close arespective first or second portion of said clip upon release from arespective first or second enlarged end portion.
 117. The fastener ofclaim 116, further comprising a first needle fixed to said first releasemechanism.
 118. The fastener of claim 117, further comprising a flexiblemember interconnecting said first needle and said first releasemechanism.
 119. The fastener of claim 117, further comprising a secondneedle fixed to said second release mechanism.
 120. The fastener ofclaim 119, further comprising a flexible member interconnecting saidsecond needle and said second release mechanism.
 121. The fastener ofclaim 112, wherein said first and second mechanical restraints comprisefirst and second coils surrounding at least a portion of said first andsecond portions of said clip, respectively.
 122. The fastener of claim121, wherein said first and second coils each comprise a memory biasedto said closed configuration and a memory shape substantially conformingto a memory shape of said first and second portions of said clip,respectively.